It is desirous and occasionally required that two or more collaborators work together on a creation while being physically separated from one another. Such a situation is generally referred to as “remote collaboration”. Collaboration, in general, involves creating and displaying text and graphics and then sharing the information created with each collaborator in real or substantially real time. This sharing may be facilitated by a system which provides a common shared work space. Working without a shared work space can limit collaboration by delaying the common understanding about a thing, task, etc. being referred to, limiting the ability of one collaborated to visually add to or comment on the work of another collaborator, causing significant delays in the chain of communication between the collaborators, etc.
There exists in the art a number of devices or systems allowing or facilitating various degrees of use of a shared work space. Some for example, allow remote users only to use the work space. For example, U.S. Pat. No. 4,400,724 issued to Fields teaches presenting images of both a user and a document or the like, and allowing some degree of interactive use of the document. Fields discloses a video teleconferencing system where a number of collaborators can interactively communicate via a plurality of interconnected monitors and cameras. A document is imaged by a video camera suspended above a target area where the document is located. Likewise, gestures related to the document made within the target area are imaged by the same video camera. The images are presented on the monitors of other collaborators. The other collaborators may modify the image by marking over their own target areas or referred to the image by gesturing in the appropriate locations in their own target area. The composite of the document's image modifications and gestures are distributed for viewing by collaborators on their monitors, which are physically separate from their target areas, in real time.
Other collaborative systems use computer monitors only. CU See Me and Microsoft Net Meeting are examples of these types of collaborative systems. Consequently, these systems make it more difficult for collaborators to quickly alter the collaborative subject matter.
It has been determined that a number of disadvantages exist in the present devices or systems of the type discussed above. First, in general in the art there are no devices having writing surfaces which coincide with the viewing surfaces for all users. This disparity between input location and output location can make it unnatural or difficult to collaboratively instruct in a user drawing. What is desired is a system in which the writing and viewing surfaces coincide to allow shared marking directly on the presented image. Secondly, those devices or systems that transmit full video signals required high bandwidth transmission between the user sites. This may be prohibitively expensive and render unsatisfactory images when transmitted according to developing standard communication protocol, such as NTSC analog video or digital video transmitted over ISDN or used with common data compression schemes, etc.
Accordingly, what is needed is a system having a more limited transmission bandwidth requirement than previously available.